Time out is starting to Not Work At All - at wits' end with ds!!

[raisingrrrl]

Ds is 2 and generally a bit of a handful. I started to do time out with him, for things like hitting, biting (especially on his baby sister) and not listening. It worked for a little while, but recently he's started to do something naughty or aggressive and then put himself into time out, so he's obviously thinking that it's ok, so long as he does his time.

I don't really enjoy using time out as a form of punishment but if it's a case of that or walloping him (which I've been close to on occasion, when he's been deliberately hitting dd) then I feel that time out is the better of two evils. But it's clearly not working very well at all, so if anyone has any better ideas or advice, that would be great!

What about removal of one of his special treats or priviledges?
My boys were (still are) creatures of habit and looked forward to certain little things that were built in the daily routine.I used to work my way through a list and cancel a treat after one clear warning.
For example DS1 would always resist getting into the car, it become quite a wrestling match. I would tell him to get in nicely or no trip to the park / T.V.time/ etc.
It's true he would end up some days losing them all but in general it worked. I never stopped bedtime story though!